Added demo back cover copy #bruce #time 45m

Also eliminated Scope.default from example

BookCover.md

@@ -4,4 +4,7 @@ Subtitle: A New Paradigm for Creating Reliable, Adaptable, Testable Systems
 Authors: Bill Frasure, Bruce Eckel, and James Ward  
 ISBN for print book: 978-0-9818725-7-5  
 Cover Price: $35  
-Back Cover Copy: TODO  
+Back Cover Copy:    
+A new paradigm called "Effect Oriented Programming" has emerged for building more reliable, adaptable, and testable systems. 
+By separating "side effects'' from the "pure" parts of a program you gain some super-powers for handling errors, applying timeouts & retries, and testing unreliable parts in isolation. 
+This book introduces the concepts of Effect Oriented Programming using simplified code examples and clear explanatory prose.

Chapters/03_Superpowers.md

@@ -322,7 +322,7 @@ The retries do not succeed so the fallback is applied.
 
 ## Finalization
 
-To ensure that something happens after an Effect completes, regardless of failures, we use `withFinalizer`:
+To ensure that something happens after an Effect completes, regardless of failures, we can attach `withFinalizer` to any Effect:
 
 ```scala 3 mdoc:silent
 val effect5 =
@@ -331,7 +331,7 @@ val effect5 =
 ```
 
 `withFinalizer` expects a function as its argument; `_ => logUserSignup` creates a function that takes no arguments and calls `logUserSignup`.
-`withFinalizer` attaches this behavior without changing the types contained in the original Effect.
+`withFinalizer` attaches this behavior with no impact on the types contained in the original Effect.
 
 ```scala 3 mdoc:runzio
 override val bootstrap = happyPath

Chapters/04_Initialization.md

@@ -515,6 +515,15 @@ To provide `BreadHomeMade`, we need `Dough` and an `Oven`.
 
 ## Dependency Cleanup
 
+We briefly saw `withFinalizer` in the [Superpowers](03_Superpowers.md) chapter.
+There's more to it, however.
+How does `withFinalizer` know when to perform its finalization?
+It uses `ZIO`'s *scoping*.
+
+[[ Maybe an intro example here; we'll see ]]
+
+### A Safer Oven
+
 An Effect without outstanding dependencies can be used to construct a `ZLayer`.
 This will correct a dangerous oversight: we heat up our `Oven`, but never turn it off!
 An `OvenSafe` turns itself off when it is no longer needed.
@@ -526,14 +535,13 @@ import zio.Console.*
 
 object OvenSafe:
   val heated =
-    ZLayer.fromZIO:
+    ZLayer.scoped:
       defer:
         printLine("Oven: Heated").run
         Oven()
       .withFinalizer:
         _ =>
-          printLine("Oven: Turning off")
-            .orDie
+          printLine("Oven: Turning off").orDie
 ```
 
 ```scala 3 mdoc:runzio
@@ -545,7 +553,6 @@ def run =
     BreadHomeMade.baked,
     Dough.fresh,
     OvenSafe.heated,
-    Scope.default,
   )
 ```